Process and apparatus for sulphur bleaching animal textile fiber



LLH. MASON June 11, 1940.

PROF JESS AND APPARATUS FOR SULPHUR BLEACHING ANIMAL TEXTILE FIBERS Filed Feb. 12, 1938 Limzs flnas'on,

MEL.

vantageously bleached by sulphur fumes.

i Patented June 11, 1940 Search scum UNITED STATES PATENT OFFICE PROCESS AND APPARATUS FOR SULPHUR BLEACHING ANIMAL TEXTILE FIBER Lindsey H. Mason, Bala-Cynwyd, Pa.

Application February 12, 1938, Serial No. 190,292

Claims.

The present invention relates to sulphur bleaching of textile materials and aims generally to improve both the methods and apparatus heretofore used for treating such materials as are ad- While the invention is applicable to the bleaching of various kinds of textile materials or fibers, a preferred embodiment is herein described with particular reference to the bleaching of animal fiber materials such as woolen and worsted yarns.

In bleaching woolen and worsted yarns, for example, it is often desirable to double bleach the yarn, by first bleaching with peroxide or some oxidizing agent to remove the color from those pigments which are affected by oxidation, and then later to subject the thus bleached yarn to a reducing reaction by stoving in sulphur fumes in a sulphur house to remove color from other pigments, in order to produce a permanent white.

This stoving process was merely the exposure of wet or damp yarn to the fumes of burning sulphur (sulphur dioxide gas), in a carefully confined chamber, called a sulphur house for a period of ten or more hours, usually overnight. The sulphur dioxide gas combined with the water of the damp yarn forming sulphurous acid (H2803) gave the bleaching action, and is referred to in the art as the sulphurous acid and sulphur dioxide bleach. Apparently the bleaching action is the result of a reducing reaction taking place in the yarn, as yarn immersed in liquid sulphurous acid will not bleach satisfactorily. Nor will dry yarn exposed to sulphur dioxide gas bleach satisfactorily.

Sulphur bleaching, according to the prior practice, consisted. in taking the peroxide bleached yarn, which had been washed, and while still wet or damp, was removed to the sulphur house usually by hand trucks where it was spread out and hung on rods or poles. The sulphur houses were usually on the roof of the building or in some remote portion of the plant because the escaping sulphur dioxide gas is disagreeable and harmful to the lungs and is apt to damage goods which are not to be bleached. After the yarn had been spread or hung on the rods or poles, a charge of sulphur was placed in a suitable receptacle and ignited and the house was then tightly closed against the entrance of air, except a limited amount adjacent the sulphur port to support combustion. The room was carefully constructed against the entrance of air as not to permit the formation of condensed acid liquor with traces of sulphuric acid, which is dropped upon the goods, spoiled and damaged the yarn. The charge of sulphur was usually sufficient to last ten or more hours as numerous inspections of the yarn at shorter intervals showed that a satisfactory bleach was not obtained in less time. Usually the yarn was left in the sulphur house overnight. After the charge of sulphur had completely burned out and the required time for bleaching elapsed, the sulphur house was opened to permit the escape of unabsorbed fumes to enable the workmen to enter the house and remove the yarn. As it was difiicult to get the house completely ventilated and free of sulphur fumes, the workmen often worked under disagreeable and unhealthy conditions. The sulphur bleached yarn was then piled in trucks and removed to a drying room for final drying, and in some instances was first washed to remove all traces of sulphur dioxide odor.

In addition to the long time required for such sulphur bleaching and the disagreeable and unhealthy conditions attendant thereto, the prior stoving methods had many other disadvantages. The wet yarn, hanging on the rods, for so many hours became stretched and had an inferior appearance, which was not entirely removed by the subsequent drying. Furthermore, notwithstanding the care to exclude outside air, condensation or acid liquor often collected on the ceiling of the sulphur house and dropped upon the yarn, soiling or damaging it.

Notwithstanding that the admission of air to the sulphur house during the burning of sulphur was, in the prior processes, attendant with the disadvantages of accelerating the formation of damaging acid liquor, I have discovered that air may be circulated through the sulphur bleaching chamber in such velocity as to prevent the condensation and presumably creates an oxidizing atmosphere which materially accelerates the bleaching action. With the preferred method and apparatus, according to the invention, it is possible to produce a highly satisfactory bleach in one hour, thus permitting the yarn to be bleached in a sufiiciently short time that it will not be damaged by stretching.

My invention may be utilized in various embodiments either for the continuous sulphur bleaching or stoving in a sulphur house, one of the most satisfactory forms being shown in the accompanying drawing, in which Fig. 1 is a diagrammatic longitudinal sectional view through one type of apparatus, constructed in accordance with the invention and suitable suitable manner, as by tracks or rails, as shown for sulphur bleaching of yarns continuously;

Fig. 2 is a detail sectional view of the track for supporting the active run of the conveyor chains;

Fig. 3 is a similar view of the track for supporting the idle or return run of the conveyor chain; and

Figs. 4 and 5 are plan and elevation views respectively of the section of the conveyor chains.

For convenience in explaining the nature of the invention, the process and apparatus will be described as for sulphur bleaching woolen and worsted yarn in skeins, although it is to be understood that the invention is applicable to the bleaching of textile materials in other forms, as for example fibers, piece goods or fabricated articles.

My invention, in its broader sense, comprises subjecting the damp or moist material to the fumes of burning sulphur (sulphur dioxide) in a bleaching chamber while establishing a forced circulation of air through said chamber during the time the material is in contact with the sulphur dioxide.

According to the illustrated embodiment of the invention the sulphur bleaching chamber l0 may be constructed of suitable material, as for example, wood, and is elongated and of desired width, height and length. Advantageously,

though not necessarily, it may be located on the roof of a building, or at some plane elevated above the level of processing apparatus which may be the washers and extractors commonly employed in preparing the yarn in a damp or moist condition for sulphur bleaching. Conveniently the washers and extractors may be on a lower level, in which case the chamber 10 may be provided with an inclined loading chamber ll. Advantageously the rear end of the sulphur bleaching chamber l0 communicates with a continuous drying chamber l2 of suitable length, though it will be apparent that these need not be connected to form a continuous chamber.

- A suitable conveying means is provided for conveying the material to be bleached through the loading chamber ll, bleaching chamber II] and drying chamber 12, and when treating yarn in skein form while it is hung on poles, this conveyor may be advantageously formed of opposed chains I3 on opposite sides of the chambers, trained over sprockets l4 and driven by a suitable driving means 15, preferably a variable speed reduction gear drive. The conveyor chains may be composed of a plurality of links (see Figs. 4 and 5) each of which comprises a pair of side frames l6, journalled at one end to a roller [1, and formed with a pole-receiving notch I8 on one edge. The rear edges of the notches 19 are preferably curved so as to securely hold the ends of the poles P on the chain during the upward travel of the poles from the loading end of the chamber H to the bleaching chamber In. The opposite edges 20 may be straight or inclined outwardly for the ready discharge of the poles from the descending conveyor at the discharge end. The opposite ends of the side frames are pivotally connected to the roller end of the adjacent link so that the conveyor chains are made up of a series of notched links. Thus the poles P with skeins of yarn spread thereon may be placed on the conveyor with the ends of the poles seated in the notches [3, so that a succession of poles of yarn are moved progressively through the chambers H, H) and i2.

The chains are preferably supported in any in Figs. 2 and 3. As shown in Fig. 2, the rail 2| may be relatively broad to provide a track for the roller l1 and chain on its active run, when there is considerable weight on the chain due to the loaded skein rods. On the return run, however, the track 22 may be narrow to be positioned between the depending notched frames l6 and provide a track for the rollers IT.

The bleaching chamber 10 may be provided with one or more recesses 23 at or near the entering end and, if desired, spaced throughout the length of the chamber ID for the sulphur burning pot or receptacle. The number and spacing of these recesses is such that the fumes from the sulphur burning in them will fill the bleaching chamber and be absorbed by the moisture of the yarn.

In order to accelerate the bleaching action, as well as to prevent condensation within the bleaching chamber, I establish'a forced circulation of air through the bleaching chamber as the material is brought into contact with the sulphur fumes. This may be accomplished by the use of blowers or fans 24 adjacent the loading end of the chamber II for forcing air into the bleaching chamber, and an olftake or ventilator 25 in the ceiling of the chamber 10, and preferably located at or near the rear end of the bleaching chamber HJ. Fans 26 also may be employed in the drying chamber and arranged to blow air onto the skeins as they leave the bleaching chamber to remove substantially all traces and odors of sulphur dioxide gas. The arrangement of fans, one at the entrance end of the loading chamber H andthe other in the drying chamber l2 serveto keep the obnoxious sulphur fumes from the workmen at the opposite loading and take-off ends ofthe apparatus, as well as to set up the desired circulation of air and sulphur fumes.

To assist in preventing the sulphur fumes from reaching the opposite ends of the apparatus where workmen are stationed,.loading and unloading the skein rods from the conveyor, the opposite ends of the bleaching chamber 10 may be provided with baffles 21 extending across the chamber and of a height approximately equal to the height of the chamber adjacent the sulphur burning recesses 23. The sulphur fumes are heavier than air and tend to descend and hence these baflles are effective to some extent in keeping the fumes from the loading and discharging ends. The conveyor chainsare trained over idler pulleys 28 above these baffles, so that as the skein rods with the skeins of yarn depending from them are successively brought over the baffles, a series of curtains are successively presented which contribute in keeping the fumes from the loading and discharge ends.

In practice the skeins of wet yarn hanging from the poles P are moved into the bleaching chamber and there come into contact with the sulphur fumes (sulphur dioxide gas) which reacts with the water on the wool, forming sulphurous acid (HzSOs), the reaction taking place on the yarn and effecting the bleaching. The bleaching chamber is of course filled with sulphur fumes and as the speed of travel of the conveyors is such as to require from one to two hours for each pole to traverse the bleaching chamber, there is a continuous absorption of sulphur dioxide gas by the water in the yarn, and therefore a continuous bleaching reaction. This bleaching reaction takes place in a draft of sub- G. warmer-ru tr, Ura 1 51mg oeril'cll hoom tars l catalo record.

5 f E A a v A A Qalldiii r Limits a acres, I l m it U 2,204,044 3 stantial velocity produced by the fans 24 and in an oxidizing atmosphere of a forced air curventilator 25, so that there is a continuous evaprent. crating or oxidizing atmosphere which accel- 3. The method of continuously sulphur bleacherates the bleaching as well as prevents coning textile materials which consists in spreading densation within the chamber l0 such as might the material upon a rod-like support and progres- 5 damage the yarn. sively moving the spread material to be bleached As the yarn enters the drying chamber l2, it is through a bleaching chamber, subjecting the maquickly dried by hot air supplied by heating coils terial while wet to the fumes of burning Su p 29, while the drying is accelerated by blowing admitted to the chamber at points removed from air over the yarn by means of the fans 26. This the entrance end thereof, and blowing air into 10 also, as stated above, aids in removing obnoxious the entrance end of the chamber to create a cirsulphur di xide odors from the yarn. The poles culating oxidizing atmosphere and to substantialcarrying the bleached dry yarn may be easily y p v the seepage of d p u es t0 removed at the take-off end by workmen. h entrance end of s id m er.

The particular a ti th takes place b 4. The method of sulphur bleaching textile and 15 tween the sulphur fumes, th w t r on h yarn, like materials which comprises moistening the and the air circulating through the chamber is al a d p o ressively subjec batches not at this time definitely established. It has thereof to the bleaching act of fumes of burnbeen found in practice that the time required g Sulp u forcibly blowing Over t e mafor a satisfactory commercial bleach is mateteriel While it contacts with the sulphur fumes rially shortened, when a circulation of air is set in Such ocity as will Prevent de sat o of up through the bleaching chamber, and hence Said Sulphur fumes, and then p ve y Subthe air appears t provide an evaporating or jecting the batches of bleached material unioxidizing atmosphere acceleratjng t bleaching formly to a drying heat without intermediate action. Furthermore, the actual use of the inhandling of Said material- 25 vention and apparatus illustrated shows no con- Apparatus for the continuous Sulphur densation on t i i or other parts of eham bleaching and drying of wet textile material comber It), thus producing a very different effect, prising an elongated open .ended housing, ventifrom merel permitting air to enter the lating outlet dividing said housing into a bleachphur hou 01 th 1 Stevihg methed ing and drying chamber, an endless conveyor for 30 Woolen and worsted yam bleached according conveying said material progressively through to my invention has improved physical character- Said bleaching and drying chambers means for istics over yarn bleached by the prior process. supplying fumes of burning sulphur to said- Due t th materially Shortened time required bleaching chamber in contact with the wet mate- Ior bleachi the yarn in the um is not rial, and means located ahead of said sulphur 35 stretched to the same extent as heretofore, thus fume Supplying means and in said drying chamenabling th yarn t retain more of its natural ber for blowing air in opposite directions toward and original r il1 Also as the amount of said outlet to create a forced circulation through p ur dioxide gas that will be absorbed in the said bleaching Chamberyarn and made available for bleaching, is di- Apparatus for the continuous Sulphur o rectly proportional to the water content in the bleaching and drying of Skeins of Wet textile yarn, the water content may be increased, if determ] which has been hung upon poles comprissired, without serious danger of damaging the ing an elongated housing having Open loading and wool by undue stretching Moreover the various takeoff ends, a ventilating outlet between said skeins are uniformly stretched and bleached, due ends dividing Said housing into bleaching and 45 to the fact that the successive skeins are subdrying chambers endless corw-eymg chains jected to a uniform treatment for uniform time, ing a series of poler'eceiving notches for conveywhich was impossible accqrding to the prior ing the skein laden poles from the loading to methods. the takeoff ends of the housing, means for supply- The method and apparatus herein illustrated ing fumes of burning sulphur to sa d bleaching 5o permit of simpler, cheaper and quicker sulphur chamber in contact with said wet material, and

bleaching th possible heretgfore, resulting in a means located adjacent the loading end and takeconsiderable saving in the time required for and o f ends of said housing for blow a towa d the cost of handling and bleaching at ri l, 11-, the outlet to create a forced circulation through is more pleasant and healthful to the workmen sa d bleaching chamber d prevent th pa 56 who formerly were brought into contact with the of sulphur fumes to the loading and takeoff ends. obnoxious sulphur f 7. Apparatus for the continuous sulphur Obviously, the invention is not to be restricted bleaching and drying of Skeins 0f W t e t e atto the details of construction or the specific steps 1911 which has been hung p P0168 p s ng as above described. an elongated housing having open loading and 60 60 I claim; takeoff ends, a ventilating outlet between said The method f sulphur bleaching texti1ema ends dividing said housing into bleaching and terials which comprises spreading the material qrymg chambers endless.c9nveylng chains upon a rod-like support and subjecting the a Series pole'recelvmg notches spread material in a wet condition to fumes of gfi i Sken the loadmg to burning sulphur and blowing air onto said mae a 60 en S o e f l for vary" ing the speed of travel of said skelns through the tonal while it is being sub ected to the sulphur housing, means for supplying fumes of burning g -h sulphur to said bleaching chamber in contact in mtmuouslr sullfhur f with said wet material, and means located adja- 70 g ex 1 e materials which consists in spreadl cent the loading and takeoff ends of said housing the mammal on a Support progresslvijly for blowing air toward the outlet to create a moving the spread material to be bleached while forced circulation through said bleaching chem- Wet through a bleaching Chamber, a d bj ber and prevent the seepage of sulphur fumes to ing the material to the fumes of burning sulphur the loading-and takeoff ends. 76

i 8. Apparatus for sulphur bleaching wet textile material which has been spread upon rod-like supports, comprising an elongated bleaching chamber, endless travelling conveyor members mounted in said chamber adjacent opposite sides thereof, said conveyor members being adapted to removably support and transport the materialcarrying rod-like supports, means for moving said conveyors to move the material through the bleaching chamber from the entering and to the exit end thereof, means intermediate the entering and exit ends of the chamber for admitting fumes of burning sulphur to said chamber, and means positioned in advance of said sulphur admitting means for forcibly blowing air into said chamber.

9. Apparatus for sulphur bleaching wet textile material which has been spread upon rod-like supports, comprising an elongated bleaching chamber having entering and exit ends for said material, a travelling conveyor mounted in said chamber adapted to removably support and transport the material-carrying rod-like supports, means for moving the conveyor to move the material through the bleaching chamber from the entering end to and out of the exit end thereof, means intermediate the entering and exit ends of the chamber for admitting fumes of burning sulphur to said chamber, a ventilator adjacent said exit end, and means positioned in advance of said sulphur-admitting means for forcibly circulating air through said chamber and out of said ventilator in suflicient volume and velocity to prevent condensation in said chamber.

10. Apparatus for sulphur bleaching wet textile material which has been spread upon rod-like supports, comprising an elongated chamber having a substantially horizontally disposed bleaching section and a downwardly inclined loading section communicating with the bleaching section at one end, a travelling conveyor mounted in said chamber adapted to removably support and transport the material-carrying, rod-like supports upwardly through said loading section and laterally through said bleaching section, means for moving the conveyor to move the material from the entering end of the loading section to the exit end of the bleaching section, means intermediate the entering and exit ends of the chambers for admitting fumes of burning sulphur to said chamber, a ventilator adjacent said .exit end, and means positioned in advance of said sulphur-admitting means for forcibly blowing air into said chamber and out of said ventilator.

LINDSEY H. MASON. 

